Optimizing the compressive strength of hydraulic cement, e.g., Portland cement, has been well-studied in the engineering and chemical arts. Many factors influence the compressive strength of cement compositions such as concrete, e.g.: the water-cement ratio (the weight ratio of water, exclusive of that absorbed by the aggregates, to cement); cement content or cement factor; temperature; physical properties and chemical composition of the cement. As to the chemical composition of the cement, chemical admixtures have been used to enhance the compressive strength of the cement composition (for brevity, the term "concrete" will be used herein to encompass concretes, mortars and pastes unless otherwise noted.) For example, alkanolamines such as ethanolamine, diethanolamine, triethanolamine; alkali and alkaline earth metal thiocyanates and nitrites; and halides are known to shorten the set time as well as enhance the one-to-three day compressive strength of cements.
Early, i.e., 1-3 day, compressive strength, is of some importance in the precast and prestress concrete industry, and for other uses where it is desirable and/or necessary for the poured concrete to be subjected to some immediate stress, i.e., foot traffic, etc. While early strength cements are available, they are not always suitable for a particular task. As such, it has been desired to find a chemical additive for Portland cement (which can be added before or after mixing with water and/or aggregates) which will increase the early compressive strength of the hardened concrete.